Research Progress of AP2/ERF Transcription Factor Family in Important Crops

Plants have the ability to show responses against various environmental stresses. It is one of the necessities to understand stress response mechanisms to improve crops productivity and quality, under the stressed condition. The AP2/ERF transcription factors are one of the putative candidates that are involved in the regulation of biotic and abiotic stress. Most of the research has been conducted on functional analysis of AP2/ERF genes in many plants; however, a comprehensive review is required to show a broad picture of functionally characterized AP2/ERF in different plants. In this study, a comprehensive review is carried on genome-wide studies of AP2/ERF gene family and their evolutionary divergence in plant species including mustard (Arabidopsis, brassica), cereal (rice, wheat, maize, sorghum), and fiber (upland cotton and island cotton). Review exhibited that AP2/ERF superfamily is classified into four sub-families e.g. AP2, DREB, ERF, RAV and solicit, in which the ERF was the largest sub-family of AP2/ERF superfamily. Each subfamily was further divided into multiple groups and sub-groups. Furthermore, each plant species showed different number of paralogs showing correspondence to the plant genome size .e.g. higher genome possess higher gene copy number. The change in copy number may be due to either tandem gene duplication or whole genome duplication during evolutionary adaptation that developed special feature in plant species under environmental stresses. Moreover, current study also surveyed on the expression of AP/ERF genes with the conclusion that expression of AP2/ERF produced tolerance against biotic and abiotic stresses. However further studies are required to improve crops resistance by studying the same variables and gene families in different plants.